give notice vs let someone go

give notice

verb
  • To announce one's intent to leave a job; to inform an employer that one is leaving. 

  • Used other than figuratively or idiomatically: see give, notice. 

let someone go

verb
  • To dismiss someone from an employment position or a relationship. 

How often have the words give notice and let someone go occurred in a corpus of books? (source: Google Ngram Viewer )